GaIn ‐Induced Polarization Control in PVDF for High‐Efficiency Energy Harvesting and Instantaneous Wireless Sensing

Achieving high‐performance polymer‐based piezoelectric–triboelectric nanogenerators (PTNGs) remains challenging due to the limited electroactive phase content and inefficient dipole alignment in polymer matrices. Although many doped nanoparticles can enhance PTNG performance, the fundamental mechanisms behind these improvements are often unclear. In this work, guided by molecular dynamics (MD) and density functional theory (DFT) simulations, we present a doping strategy using eutectic gallium–indium (GaIn) alloy to construct β‐PVDF‐GaIn composites with markedly improved piezoelectric and triboelectric properties. The simulations reveal that Ga and In atoms preferentially coordinate with fluorine atoms in PVDF, stabilizing all‐trans chain conformations and promoting dipole ordering under an external electric field. Simultaneously, GaIn and its surface oxide layers (Ga 2 O 3 /In 2 O 3 ) function as electron‐trapping centers in the PVDF during triboelectric contact, capturing transferred electrons and enhancing interfacial charge accumulation, which facilitates improved charge retention and enhances the electric output of the device. The resulting β‐PVDF‐GaIn composites exhibit significantly enhanced β‐phase content of 91% and improved piezoelectric and triboelectric outputs. Under optimal conditions, β‐PVDF‐GaIn/PA6 PTNG achieves a peak‐to‐peak voltage output of 1831 V, a current density of 214.3 mA m −2 , a charge density of 254.4 μC m −2 , and a maximum power density of 83.8 W m −2 . Based on this PTNG, we develop a fully self‐powered instantaneous wireless sensing platform, enabling real‐time monitoring of human motions. This study offers insights into the development of high‐performance piezo/triboelectric films and their integration into self‐powered sensing applications.